The GC multiplayer on XIII is all kinds of screwed up. I don't believe you can pick your character, at all. It seems characters are assigned to controller ports. L4M3! The painful voice acting also irritated to no end. They had no power, no umph, so I really question why they had it there in the first place. Comic books don't talk, right?
As a side note, what is UP with Ubi Soft and cliffhanger endings? I wouldn't mind it so much except that they always do it for games they probably have no intention of making a sequel to, like XIII and Beyond Good and Evil.